Behavior-related changes in canine heart rate and heart rate variability during short-term measurement

Cardiac function is influenced by both physiological and emotional factors, with heart rate variability (HRV) serving as a key indicator of health and wellbeing. Despite the growing interest in utilizing short-term cardiac measures in canine science, the behavioral aspects of HRV in domestic dogs ( Canis familiaris ) remain largely unexplored. This study aimed to provide reference values for short-term HRV to aid future research on canine behavior in medium-sized, mesocephalic and dolichocephalic dogs, to examine differences in HRV during typical canine behaviors, and to develop practical tools for the analysis of canine cardiac function. We assessed heart rate, HRV, and physical activity of 29 dogs across five behavioral states (Resting, Playing, Panting, Spontaneous sniffing and Food searching) and investigated how these behaviors influenced time-domain and frequency-domain HRV parameters. The impact of physical activity, sex, neutered status, age, height, and weight on these parameters within the specific sample was also assessed. Both time-domain and frequency-domain parameters were affected by the behaviors. Precisely, HRV generally decreased with behavior-related physical activity (root mean square of successive differences, RMSSD; Resting vs. Playing, p < 0.001; and Resting vs. Searching for food, p < 0.001). However, RMSSD was significantly lower during Searching for food compared to Spontaneous sniffing (p = 0.012), despite similar activity levels, indicating higher emotional arousal when searching for food. Overall, the high-frequency component (HF power) and RMSSD differentiated well between the distinct canine behaviors. Also, physical activity (measured as 3D acceleration) was the most influential background variable in this highly specific sample, correlating with HRV parameters and depending on the behavior. • Dogs’ HR and HRV were strongly associated with their behavior. • Of all HRV parameters, RMSSD and HF showed the most robust differences between distinct behaviors. • High intensity breathing in dogs is related to elevated HR and reduced HRV. • Both behavioral and emotional factors modify HR and HRV in dogs.